As a presbyterian who adheres strongly to the priesthood of believers and the Five Solas, I cannot help but be saddened by this. I embrace those in the Roman Catholic church who have accepted salvation in Christ alone as my brothers and sisters, but I cannot help but be grieved at this step by the Scottish Presbyterians.
Orthodox Catholics and orthodox Presbyterians both realize that about the only joint "liturgy" they could share would be a common recitation of the Lord's Prayer and the Apostle's Creed.
I would point out that Catholics also believe in the priesthood of all believers.
The distinction is that Catholics believe that there is a common priesthood and a sacrificial priesthood whereas Presbyterians do not believe that there can be a sacrificial priesthood.
In practice, any adult Catholic male - married or unmarried - can, if called to the order of deacon, perform the role that Presbyterian pastors are called to perform: preside at baptisms, solemnize marriages and burials, communicate the people in the Lord's Supper (not consecrate the Eucharist, but Presbyterians do not acknowledge a consecration), proclaim the Scriptures from the pulpit and preach God's Word.